Field of the Invention
The invention relates to a touch display driving technique, and more particularly to a touch display device that maintains touch sensing accuracy and sensitivity and display quality and a method for driving the same.
Description of Related Art
Due to the ability to provide users with more intuitive and convenient ways of manipulation, touch display devices gradually become mainstream and are extensively adopted in a variety of consumer electronic products in recent years. Among various types of touch display devices, a touch display device having a capacitive touch panel accompanied by a liquid crystal display panel (hereinafter referred to as a “capacitive touch display device”) is used most extensively for having good properties such as sensitive response, accurate detection of touch points and small size.
The capacitive touch display device detects the position of the touch point by detecting a capacitance variation of a touch panel, and the capacitance variation on the touch panel is in turn influenced by coupling effects of a display panel. Therefore, if driving/detection is performed to the touch panel during a display period that data is written to the display panel, the detected touch data may be disturbed by pixel voltages and be inaccurate. However, if driving/sensing is performed to the touch panel only during a blank period that no data is written to the display screen, the touch sensing frequency will be limited to the refresh frequency/frame per second (FPS), which causes reduction in touch sensitivity. Therefore, the design and arrangement of a driving sequence between the display panel and the touch panel is rather important.